Tag: physics

Questions Related to physics

$10^{-3}$ gram is called the

physics physical quantities and measurement measurement of small and large distances measurement of distance unit of fundamental quantities

  1. kilogram

  2. milligram

  3. decigram

  4. microgram

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Correct Option: B
Explanation:

1 milligram (mg) = $10^{-3}$ gram (g)

The Hubble Space Telescope is designed with ____________  hyperbolic mirrors is known for good imaging performance over a wide field of view. 

physics universe and space xx radio telescope and space telescopes optical instruments : telescope

  1. two

  2. four

  3. three

  4. many

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Correct Option: A
Explanation:

Hubble space telescope is reflecting telescope it is designed with TWO hyperbolic mirrors. A curved primary mirror is the basic optical element that creates an image at the focal plane. And secondary mirror was added to modify the optical characteristics for visual observation.

Which among the following is not true for Hubble ST?

physics universe and space xx radio telescope and space telescopes optical instruments : telescope

  1. Hubbles observations found that black holes are common to the centers of all galaxies.

  2. Hubble's Telescope was first to found the traces of water on Earth.

  3. Hubble Deep field and Hubble Ultra Deep Field images reveal galaxies that are billions of light-years away.

  4. Astronauts used the telescope to observe distant supernovae.

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Correct Option: B
Explanation:

We know that Earth has water, blue planet, 71% of Earth's surface is covered in water. Hubble telescope was definitely not the first to found the traces of water on Earth. 

What is full form of GMRT ?

physics observing space: telescopes xx radio telescope and space telescopes optical instruments : telescope

  1. Ground Mobile Receive Terminal

  2. Geometric Mean Reciprocal Titer

  3. Giant Metrewave Radio Telescope

  4. General Maintenance and Repair Technician

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Correct Option: C
Explanation:

Giant Metrewave Radio Telescope (GMRT).

In an oscilloscope the vertical deflecting plates deflect the electron beam in a vertical plane.

physics option c: imaging xx radio telescope and space telescopes optical instruments : telescope

  1. True

  2. False

  3. Nither

  4. Either

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Correct Option: A

An observer looks at a distant tree of height 10 m with a telescope of magnifying power of 20. To the observer the tree appears:

physics observing space: telescopes xx radio telescope and space telescopes optical instruments : telescope

  1. 10 times taller .

  2. 10 times nearer .

  3. 20 times taller .

  4. 20 times nearer .

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Correct Option: D

The focal length of objective and eye-piece of a telescope are $200\ cm$ and $5\ cm$ respectively. Final image is formed at least distance of distinct vision. The magnification of telescope is

physics option c: imaging xx radio telescope and space telescopes optical instruments : telescope

  1. $20$

  2. $24$

  3. $30$

  4. $48$

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Correct Option: D

If $\log\ (-2x)=2\log\ (x+1)$, then $x$ can be  equal to

physics logarithms introduction to logarithm logarithmic notation exponential and logarithms

  1. $-2+\sqrt {3}$

  2. $-4+2\sqrt {3}$

  3. $-2-\sqrt {3}$

  4. $-4-2\sqrt {3}$

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Correct Option: A,C
Explanation:

We have,

$ \log \left( -2x \right)=2\log \left( x+1 \right) $

$ \Rightarrow \log \left( -2x \right)=\log {{\left( x+1 \right)}^{2}} $


Comparing both side and we get,

$ -2x={{\left( x+1 \right)}^{2}} $

$ \Rightarrow -2x={{x}^{2}}+1+2x $

$ \Rightarrow {{x}^{2}}+4x+1=0 $


Using quadratic formula and we get,

$ x=\dfrac{-4\pm \sqrt{16-4\times 1\times 1}}{2\times 1} $

$ x=\dfrac{-4\pm \sqrt{12}}{2} $

$ x=\dfrac{-4\pm \sqrt{2\times 2\times 3}}{2} $

$ x=\dfrac{-4\pm 2\sqrt{3}}{2} $

$ x=-2\pm \sqrt{3} $


Hence, this is the answer.

If $\displaystyle \log _3 x = 0$, then value of $x$ is equal to

physics logarithms introduction to logarithm logarithmic notation exponential and logarithms

  1. $2$

  2. $4$

  3. $1$

  4. $3$

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Correct Option: C
Explanation:
$\log _3x = 0$      

$x=3^0$   ....(since we know that $\log _ab=t\Rightarrow b=a^t$)
     
$\therefore x=1$

State true or false: 

If$\displaystyle x^y = z$, then $\displaystyle y = log _z x$.

physics logarithms introduction to logarithm logarithmic notation exponential and logarithms

  1. True

  2. False

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Correct Option: B
Explanation:

$x^y=z$
Apply log on both the sides, we get
$\therefore ylogx=logz$
$\therefore y=\dfrac{logz}{logx}$
$\therefore y=log _xz$
Hence, it is false.